Chapter 5 - Circulation And Digestion

Question 1

Veins

Answer 1

Carry blood to the heart. Have the nobles than arteries and off and have valves along the length to prevent back flow of blood (and a large lumen).

Question 2

Capillaries

Answer 2

Carry the blood through the organs and allow the exchange of substances with all living cells in the body. Are narrow thin-walled vessels.

Question 3

Heart rate

Answer 3

Adults have a natural resting heart rate of 70 bpm roughly.

Question 4

The heart has 4 chambers:

Answer 4

The offer one called atria receive blood from the vena cava on the right and the pulmonary vein on the left. The atria contract to move blood into the lower chambers known as the ventricles.

Question 5

Coronary heart disease

Answer 5

Stunt is inserted to keep blood vessels open and balloon is inflated to open blood vessels.

Question 6

Leaky valves

Answer 6

Mean the blood could flow in the wrong direction and artificial ones can be inserted to replace damaged ones.

Question 7

Blood plasma transports:

Answer 7

Carbon dioxide from organs to the lungs, urea from the liver to kidneys where urine is made and soluble products of digestion.

Question 8

Red blood cells

Answer 8

Biconcave discs which do you not to have a nucleus and contain the red pigment haemoglobin. This combined with oxygen to form oxyhaemoglobin in the lungs.

Question 9

White blood cells

Answer 9

Have a nucleus and form part of the bodies defence system against microorganisms.

Question 10

Platelets

Answer 10

Or small fragments of cells which do not have a nucleus and help blood to clot at a wound. These are a series of enzyme controlled reactions that turn fibrinogen to fibrin to form a network of fibres and a scab.

Question 11

Antigens

Answer 11

Proteins on the surface of cells which each person has a unique set of.

Question 12

Summary of the digestive system

Answer 12

The pancreas and salivary gland produces digestive juices. The stomach and small intestine are where digestions occurs due to enzymes in the digestive juices. The liver produces bile to aid lipid digestion and the small intestines is where the absorption of soluble food occurs through th villi in the walls and the large in testing where water is absorbed from the undigested food.

Question 13

Amylase

Answer 13

Produced by the salivary gland, pancreas and small intestine. It catalyses the digestion of starch into sugar in the mouth and small intestine. Work best in slightly alkaline conditions.

Question 14

Protease

Answer 14

Produced by the stomach pancreas and small intestine. It catalyses the breakdown of proteins into amino acid’s in the stomach and small intestine. Works best in acidic conditions.

Question 15

Lipase

Answer 15

Produced by the pancreas and small intestine, catalyses the breakdown of lipids to fatty acid’s and glycerol. Work best in slightly alkaline conditions.

Question 16

Optimum temperature for digestive enzymes

Answer 16

37°C

Question 17

Bile

Answer 17

Is stored in the gallbladder and released into the small intestine when food enters. It neutralises the stomach acid making the conditions in the small intestine slightly alkaline and emulsifies fat’s to increase the surface area of the fats for lipase enzymes to act upon.

Question 18

Arteries

Answer 18

Carry blood away from the heart. Have thick walls containing muscle and elastic tissue with a small lumen.